In commonly owned U.S. Pat. No. 3,726,743 there has been disclosed an apparatus for making such laminated film from two concentrically extruded thermoplastic tubes, with admission of air under pressure into the space between the tubes and into the inner tube to inflate same. The air pressures are so adjusted that the inter-tube space terminates a short distance from the extrusion head to let the two tubes come into adhesive contact with each other so as to form a laminate; further downstream, the laminate passes between a pair of pinch rolls which flatten the bonded and nested tubes so as to allow them to be wound up on a reel. A stream of air is radially trained upon the outer tube to accelerate its solidification. In this process, the plastic material undergoes a desirable molecular orientation, generally biaxial as more fully described in that patent.